The greater Baltimore, Maryland area has a large population of African-Americans and European-Americans, which makes this area most suitable to investigate differences in the exposure to prostate cancer risk factors among these two groups. We designed a new protocol that proposes molecular epidemiology and translational research studies and the collection of blood, urine, tissue samples, and survey data. Other epidemiological studies of prostate cancer have been established in recent years;however, only a few of these studies address the need for health disparity research and will have the opportunity to collect fresh-frozen tumor specimens from case subjects. Our study was implemented in two phases. The first phase, which started in April of 2005 constituted a pilot study to evaluate recruitment procedures. This phase was successful and the full study was initiated with minor changes to the protocol in April of 2006. Study participants will be African-American and European-American males who reside in Baltimore city and surrounding areas. The study will recruit 600 prostate cancer cases and 600 population-based controls. These are the current recruitment targets. However, those may increase to 1000 cases and 1000 controls with recruitment into 2015. The cases are recruited at two Baltimore hospitals, the Veterans Affairs Medical Center and the University of Maryland Medical Center. Cases will have pathologically confirmed prostate cancer. The population-based controls are identified through the Maryland Department of Motor Vehicles database, and are frequency-matched by age and race to cases. The study involves the administration of two questionnaires and collection of blood and urine from all study subjects. Fresh-frozen tumor specimens will be obtained from cancer patients where available. The two questionnaires consist of a main questionnaire and a supplemental questionnaire. The questionnaires evaluate familial cancer history, tobacco use, medication use, occupational history, socioeconomic status, and risk factors for prostate cancer. The study is supported by an epidemiological infrastructure that has been developed by our resource contractor at the University of Maryland for a lung cancer case-control study. This lung cancer study is ongoing, and the controls that are recruited for the prostate cancer study are joint controls with the lung cancer study. Hence, population-based male controls recruited by our contractor have double eligibility for the concurrent lung and prostate cancer studies. To achieve an age and race matching of cases and controls in the prostate study, we will over-sample male controls in the lung study. This study and the ongoing lung study are described by a recently established website at (http://home.ccr.cancer.gov/GEMES/index.html). The website also describes the policy for collaborations involving data sharing. Study protocol and the two questionnaires can be accessed at: http://www3.cancer.gov/intra/lhc/Ambs/Prostate_Cancer_Case_Control_Study_Protocol.pdf http://www3.cancer.gov/intra/lhc/Ambs/Lung_Prostate_Case_Control_Questionnaire.pdf http://www3.cancer.gov/intra/lhc/Ambs/Prostate_Cancer_Supplementary Questionnaire.pdf Our study is aimed at identifying the differences in tumor biology and risk factor exposure that exist among African-American and European-American men. We will test the hypothesis that environmental and genetic factors contribute to the existing prostate cancer health disparity among African-Americans and European-Americans. We will also use molecular work to examine race/ethnic differences in tumor biology. Currently, we have recruited about 480 cases and 240 population-based controls and we have collected blood and urine from these individuals. Future recruitment rates are set at 80-100 cases and 120 controls per year. The participation rate of eligible subjects has been very good and 85% of the eligible case patients and 80% of the eligible population-based controls enrolled into the study. Importantly, we had the same participation rates for African-Americans and European-Americans. We also collected about 60 paraffin-embedded and fresh-frozen tumors.